<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>CSS边框旋转流光效果</title>
<style>
  .glowing-border {
    width: 100px;
    height: 100px;
    border: 2px solid #3498db;
    border-radius: 50%;
    position: relative;
    animation: rotate 5s linear infinite;
  }
 
  .glowing-border::before {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    border-radius: 50%;
    background: linear-gradient(45deg, transparent, transparent 10px, #3498db 10px, #3498db 20px, transparent 20px);
    z-index: -1;
    animation: pulse 5s linear infinite;
  }
 
  @keyframes rotate {
    from {
      transform: rotate(0deg);
    }
    to {
      transform: rotate(360deg);
    }
  }
 
  @keyframes pulse {
    0% {
      transform: scale(1);
      opacity: 0.5;
    }
    100% {
      transform: scale(1.2);
      opacity: 0;
    }
  }
</style>
</head>
<body>
<div class="glowing-border"></div>
</body>
</html>